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package org.apache.juneau.http;

/**
 * Category of headers that consist of a single enum value.
 * 
 * <p>
 * <h5 class='figure'>Example</h5>
 * <p class='bcode'>
 * 	Accept-Ranges: bytes
 * </p>
 * 
 * <h5 class='section'>See Also:</h5>
 * <ul class='doctree'>
 * 	<li class='extlink'><a class='doclink' href='https://www.w3.org/Protocols/rfc2616/rfc2616.html'>Hypertext Transfer Protocol -- HTTP/1.1</a>
 * </ul>
 * 
 * @param <E> The enum type.
 */
public class HeaderEnum<E extends Enum<E>> {

	private final String value;
	private final E enumValue;

	/**
	 * Constructor.
	 * 
	 * @param value The raw header value.
	 * @param enumClass The enum class.
	 * @param def The default enum value if the value could not be parsed.
	 */
	protected HeaderEnum(String value, Class<E> enumClass, E def) {
		this.value = value;
		E _enumValue = def;
		try {
			_enumValue = Enum.valueOf(enumClass, value.toUpperCase());
		} catch (Exception e) {
			_enumValue = def;
		}
		this.enumValue = _enumValue;
	}

	/**
	 * Returns <jk>true</jk> if the specified value is the same using {@link String#equalsIgnoreCase(String)}.
	 * 
	 * @return <jk>true</jk> if the specified value is the same.
	 */
	public E asEnum() {
		return enumValue;
	}

	/**
	 * Returns this header as a simple string value.
	 * 
	 * <p>
	 * Functionally equivalent to calling {@link #toString()}.
	 * 
	 * @return This header as a simple string.
	 */
	public String asString() {
		return value;
	}

	@Override /* Object */
	public String toString() {
		return value == null ? "" : value;
	}
}
